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« on: May 16, 2020, 02:03:33 PM »
Hi
While emulating a DX7 is definitely not my primary reason for using a PreenFM2 (this would only be scratching the surface of its enormous potential), it would still be a nice feature to be able to reproduce DX7 patches more faithfully, including those making use of operator feedback.
While I understand from what I’ve read that the PreenFM2 can’t do real time operator feedback for some fairly fundamental reasons, it seems to me that there are certain limitations of the DX7’s feedback system and certain features of PreenFM2’s engine that could be taken advantage of to produce a reasonable approximation of DX7 style operator feedback without having to resort to hours of trial and error.
I’m far from an expert on any of this stuff and my programming skills are very ‘minimal’ so there could be certain issues I’m missing that mean this wouldn’t work, and I would not be at all surprised if there are. However, please hear me out and read my full post before commenting.
Let’s have a look at the limitations and features I’m considering here (again these are according to my understanding so please correct me if I’m wrong):
DX7 Operator Feedback – Limitations
1. Only one operator at a time can have feedback (maybe not the most relevant one but worth noting).
2. DX7 uses sine waves only.
3. There are only seven distinct levels of operator feedback (or eight, counting zero feedback).
4. Feedback can’t be modulated in real time – the level of feedback for any given patch is essentially ‘fixed’.
PreenFM2 – Relevant Features & Limitations
1. User (single cycle) waveforms are possible, and can be assigned to any operator.
2. Currently only six user waveforms are allowed which may be a problem – is there any possibility to extend this number to at least seven?
Given the constraints of DX7 operator feedback listed above (sine waves only, seven levels of feedback) it can presumably only generate seven distinct feedback waveforms. If these seven waveforms were generated using a DX7 or similar instrument, or a ‘clone’ such as Dexed, would it not be possible to capture single cycle samples of each of them and convert them to PreenFM2’s format?
DX7 algorithm 32 could be used to generate the waveforms, since it’s the only DX7 algorithm that has a feedback operator in the carrier position.
They could then be loaded into the user wave slots on the PreenFM2. By assigning the appropriate waveform to the relevant operator in a DX7 patch depending on the feedback level used, would this not be likely to arrive at a reasonable approximation (at least closer than currently) of the DX7 patch?
Anyway, it’s just an idea I’ve been mulling over and I would welcome feedback from forum members who know more about this stuff than I do.
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